“飞行” means “flight,” and “检查” means “inspection.” While the Chinese term can refer literally to the periodic evaluation of navigational aids used in aviation, such as flight procedures and electronic signals, it’s more often used to mean “surprise inspection” in a more general sense. In these contexts, the word “飞行” implies the inspection is a sudden and quick procedure. The practice reportedly originated in anti-doping inspections ahead of or during sport competitions, and has been widely adopted by certifying agencies and food and drug authorities.